During gastrulation, signals from a specialized group of mesodermal cells induce neural tissue from naive ectoderm and subsequently generate pattern within the induced tissue. Little is known about the mechanism that directs these processes. To date only two factors, noggin and follistatin, fit the criteria for endogenous neural inducers. However both factors induce neural tissue of exclusively anterior character and therefore can not be the only endogenous neural inducing molecules. We will screen an expression cDNA library as well as known signaling molecules for the ability to synergize with noggin to induce neural tissue, or to alter the type of tissue induced. In addition we will also find molecules that suppress noggin function. The experiments proposed here could uncover new roles for signaling molecules already known to be expressed in embryos, as well as identify new signaling molecules. Since improper exposure to developmentally important signaling molecules such as Wnt-1 can cause tumors, understanding the signaling pathways that operate in normal development is a crucial step towards understanding how such pathways operate in the abnormal conditions that cause cancer.